Two-stroke engines having automatic suction timing device



W. SONClNl Jan. 9, 1962 TWOSTROKE ENGINES HAVING AUTOMATIC SUCTION TIMING DEVICE 2 Sheets-Sheet 1 Filed Jan. 9, 1961 Jan. 9, 1962 w. SONCINI 3,016,050

TWO-STROKE ENGINES HAVING AUTOMATIC SUCTION TIMING DEVICE Filed Jan. 9, 1961 2 Sheets-Sheet 2 FIG.3

United States Patent 3,016,050 TWO-STROKE ENGINES HAVING AUTOMATIC SUCTION TIMING DEVICE William Soncini, Milan, Italy, assignor to S.p.A. Meccanica Garelli, Milan, Italy Filed Jan. 9, 1961, Ser. No. 81,612 1 Claim. (Cl. 123-73) This invention relates to two-stroke engines having a device for automatic gradual timing of the closure of the inlet port, adapted to gradually delay closure as the rate of speed rises. With this device highest efliciency is ob tained from the engine at is various rates of speed.

The engine will be described with reference to the accompanying drawings which show an embodiment by way of example.

FIGURE 1 is a front view of the engine with the cover plate removed and the shaft sectional along line II of FIGURE 3;

FIGURE 2 is a sectional view of the engine on line IIII of FIGURE 1.

FIGURE 3 is a sectional view of the timing device on line III-III of FIGURE 1.

Reference 5 denotes the two-stroke engine cylinder, 6 is the piston thereof, 7 and 8 are the inlet and outlet ports, respectively.

The two-stroke engine is of the conventional crankcase compression type.

The timing device is arranged at one end of the engine crank-shaft 2 and comprises a rotary disc 9 from which a sector is removed over a predetermined angular width confined by the radial edges 10, 11, thereby providing a control port in the disc. The rotary disc times the fuel inlet to the engine through the above control port and suction port 7. As the engine rate of speed varies the angular position of the disc 9 with respect to the shaft 2 is automatically controlled by means of centrifugal weights 14 pivoted at 13 to a plate 12 secured to the end of the shaft 2. The centrifugal weights 14 are formed with toothed sectors 16 constantly meshing with a pinion 17 loosely mounted on the shaft 2 and having keyed thereto the disc 9.

It will be clear that as the rate of speed of the shaft 2 rises, the centrifugal weights 14 expand against the action of springs 15 thereby effecting through their toothed sectors 16 an angular displacement of the pinion 17, hence of the disc 9 to time inlet with respect to the shaft 2. The timing action is therefore gradual as the rate of speed increases.

What I claim is:

A two-stroke engine comprising a crankcase, a crankshaft rotatable in the crankcase, an inlet port in one of the end walls of the crankcase, and an automatic timing device controlling the said port comprising a support plate fixed to one end section of the crankshaft, a centrifugal weight pivotally supported from the plate including a toothed sector thereon, a pinch concentrical with the-said end section of the crankshaft meshing with the said toothed sector in a mutual arrangement whereby centrifugal force acting on the weight on operation of the engine will angularly shift the pinion in a direction opposite to the rotation direction of the shaft, spring means urging the weight towards the shaft, and a discshaped shutter member fast with the said pinion controlling the said inlet port.

References Cited in the file of this patent UNITED STATES PATENTS 852,272 Hennig Apr. 30, 1907 861,673 Parnall July 30, 1907 1,009,945 Veitch Nov. 28, 1911 2,839,036 Strang June 17, 1958 UNITED STATES PATENT OFF-ICE CERTIFICATE OF CGRRECTION Patent O 3 Ol6 O5O January 9 1962" William Soncini It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the heading to the printed specificationbetween lines 6 and 7 insert the following:

Claims priority apgslieatien Italy Jan, ll 1960 Signed and sealed this 19th day of June 1962 (SEAL) Attest:

DAVID L. LADD ERNEST W. SWIDER Commissioner of Patents Attesting Officer 

